I have a garden way mower by troy bilt that was given to me .I was going to cut the grass and had a flat tire,I can not see how to get the tire off please help

I am guessing this is a lawn tractor since most push mowers have soild rubber tires. Jack it up and insert two sizeable screw drivers into the seam between the tire and the wheel. Push the other side of the tire toward the centerline of the wheel. Pull both handles down toward the axle and you should see a gap opening up. Keep one driver stationary and work the other one around to the side. It will start to come open more easily as you work around the tire. I rearly fix these flats, just put in a inner tube that matches your tire size.